Base-line Soil and Petiole Testing
Soil and Petiole Testing
Why is it important?
Just as you would never medicate your children without knowing whether or not they actually have an infection, you need to be able to diagnose nutrient deficiencies in your vineyards. How to do it? Soil and petiole testing can provide a clear picture of what is going on in your vineyard. Once you have the soil tests, you have one side of the story, and petiole tests will give you the other side of the vine nutrient story. The soil tests will determine what nutrients are available to be taken up by the vines roots, and the petiole tests will show whether or not the roots are actually absorbing those nutrients. A soil test can indicate that the soil pH, K, Mg, and N levels are all adequate, but if the vines are still puny, something else might be the problem. This is where a petiole test comes in handy. Most likely, however, puny vines could be due to too much or too little water in the vineyard, and a large crop size will also affect overall vine size. If vine size (too big or too small) is a problem in your vineyard, work with your local extension specialist to determine the precise cause and method for correction.
Take the time to get a soil test to determine how much nitrogen you actually need. Nitrogen availability depends on organic matter in the soil, and each percent organic matter in the soil account for about 20lbs actual nitrogen/acre. Our program has a worksheet to calculate nitrogen needs based on soil tests results. I recommend you take the time to assess your individual blocks to determine nitrogen needs through soil and petiole testing. You may be surprised by what you may (or may not) need.
Petiole testing is an important aspect to your vineyard nutrition management program. We recommend that growers test petioles on annually, with soil testing being done every 3-5 years. Soil and petiole testing will provide information on what is in the soil and what is in the vines. In other words, you will be able to discern whether the nutrients from the soil are available and being taken up by the vines. See the LERGP soil and petiole testing page for information on how to collect soil and petiole samples and where to send them (within NY and PA).